Apparatus and method for handling articles



Aug. 10, 1965 A. G. FLINT APPARATUS AND METHOD FOR HANDLING ARTICLES 4 Sheets-Sheet 1 Filed April 19, 1962 INVENTOR ALAN G. FLINT BY W ATTORNEY Aug. 10, 1965 A. G. FLINT 3,199,673

APPARATUS AND METHOD FOR HANDLING ARTICLES Filed April 19, 1962 4 Sheets-Sheet 2 INVENTOR ALAN G. FLINT ATTORNEY Aug. 10, 1965 Filed April 19, 1962 A. G. FLINT APPARATUS AND METHOD FOR HANDLING ARTICLES 4 Sheets-Sheet 3 INVENTOR ALAN G. FLINT ATTORNEY United States Patent 3,199,673 APPARATUS AND MEOD FOR HANDLING ARTICLES Alan G. Flint, San Jose, Calif., assignor to FMC Corporation, San Jose, Calif., a corporation of Delaware Filed Apr. 19, 1962, Ser. No. 188,800 2 Claims. (Cl. 20979) The present invention pertains to an apparatus and method for handling articles, such as letters, and more particularly an apparatus for separating articles by removing from a procession thereof all those articles which have predetermined nonstandard flexibility characteristics.

The apparatus of the present invention has special utility in separating letters for further handling in automatic post ofice equipment. For example, certain mail sorting equipment will process letters satisfactorily only if they meet certain standards, namely if they are Within a range of standard sizes, if they are suficiently flexible, and if they are spaced far enough apart as they advance through the equipment. The feature of the sorting apparatus that forms the subject matter of the present invention is that of sorting letters in accordance with their flembility. Parenthetically, the term letter, as used herein, means an envelope and its contents or a post card, but it will be evident as the description proceeds that the principles of the invention are not limited to the separation of letters.

Accordingly, it is an object of the present invention to provide an apparatus for separating articles from a procession thereof into standard and nonstandard groups according to their flexibility.

Another object is to provide an apparatus and method for diverting flexible articles off from a path along which they are traveling.

Another object is to provide an article separating apparatus which separates articles on the basis of flexibility by the use of air pressure and which separates articles on the basis of size and spacing by electronically controlling the presence or absence of air pressure.

Another object is to provide an article separating apparatus which includes a minimum of moving parts.

Another object is to provide an article separating apparatus of the nature described which is particularly useful for separating letters which are nonstandard as to flexibility and which handles a large volume of letters without damage thereto.

These together with other objects and advantages will become apparent upon reference to the following description and accompanying drawings, in which:

FIG. 1 is a plan of an article separating apparatus embodying the present invention.

FIG. 2 is a side elevation of the separating apparatus illustrated in FIG. 1.

PEG. 3 is an enlarged, vertical fragmentary transverse section taken on line 3-3 in FIG. 1 and showing light rays in dashed lines.

FIG. 4 is an enlarged, fragmentary, vertical transverse section taken on line 44 in FIG. 1 and showing a letter as it is being deflected by an air blast issuing from a nozzle of the subject apparatus.

FIG. 5 is an enlarged detail end view of the nozzle.

FIGS. 6, 7 and 8 are diagrammatic plans showing various operating conditions of the subject apparatus as letters move through a separating station into either an acceptance channel or a rejection channel.

FIG. 9 is a diagram of an electrical system included in the subject separating apparatus.

FIGS. 10l4 are operational views taken at a position indicated by line 1010 in FIG. 1 and showing letters passing through the sensing unit of the subject apparatus.

With particular reference to FIGS. 1 and 2, the present article separating apparatus provides a frame 15 including a table 16 having a substantially horizontal supporting surface 17 and being supported by legs 18.

A conveyor assembly, generally indicated by numeral 25, is provided for conveying letters 26 (FIGS. 6-8) through the separating apparatus. This conveyor assembly (FIG. 1) includes a main conveyor 28 having a for-' ward driven roller 29, front and rear outside rollers 30, a rear input roller 31, a rear inner roller 32, and a forward inner roller 33. All of the rollers are dual, that is, have upper and lower portions, as best illustrated in FIG. 2. Furthermore, all of the rollers are mounted on axles 35 which are supported in the table 16 and project up from the supporting surface 17. The main conveyor also provides upper and lower vertical bolts 37 respectively guided around the upper and lower portions of the various rollers and in vertically spaced relation to each other so as to provide a horizontal slot 39 which is relatively narrow compared with the width of a letter (FIG. 4). The belts also provide an inner run 4d (FIG. 1) which extends generally longitudinally of the table. Upper and lower backing plates 42 are mounted on the table in front of the forward inner roller 33 for slidable engagement by the upper and lower belts, respectively, of the inner run.

The conveyor assembly 25 also includes a rear auxiliary conveyor 50 (FIGS. 1 and 2) having a forward driven roller 51 (FIG. 1), front and rear outside rollers 52, and a rear input roller 53, all of which are mounted on the table 16 in a manner similar to the rollers 29-33. Furthermore, upper and lower belts 55 circumscribe the input and forward rollers and bear against the outside rollers so as to provide an inner run 56 releasably bearing against the inner run from the roller 32 to the roller 33; a return run 57; and a horizontal slot 58 (FIG. 2), the latter being in the same plane as the slot 39.

Still further, the conveyor assembly 25 includes a for Ward auxiliary conveyor 65 (FIGS. 1 and 2) providing a forward driven roller 66 (FIG. 1), a rear roller 67, and an intermediate roller 68, all of which are mounted on the table 16 like the rollers 29-33. Upper and lower belts 69 are trained about the forward and rear rollers and bear against the intermediate roller thus providing an inner run 70 releasably bearing against the inner run 40 from the roller 67 to the roller 68 and a horizontal slot 71 coplanar with the slots 39 and 58.

It is significant, therefore, that the described conveyor assembly 25 has a rear section 75 extending along a sensing path 83 from the input rollers 31 and 53 to the I L forward inner roller 33, a main forward section 76 prosupporting surface 17 so as to define a rejection channel 81 between the auxiliary forward section and the block, an acceptance channel 82 between the main forward section and the block, and a separating station 85 between the forward sections and between the block and the juncture 78. By providing the block with a rear edge 87 which is upwardly forwardly inclined from the table, the articles move into one channel or the other without interference by this edge. Furthermore, a rejection chute 88 is attached to the table 16 forwardly adjacent to and in alignment with the rejection channel 81 for receiving letters 26 passing through the rejection channel.

For motivating the conveyor assembly 25, a main drive motor 92 (FIG. 1) is mounted under the table 16 and drives main and auxiliary output pulleys 94 and 95 in opposite directions through a gear box 93. A main driving belt 97, which extends around the main output pulley and an idler roller 98, rotatably drives the forward driven roller 29 of the main conveyor. A forward auxiliary driving belt 100, which extends around the auxiliary output pulley and an idler roller 101, rotatably drives the forward driven roller 66 of the forward auxiliary conveyor. Finally, a rear auxiliary driving belt 103 passes around another section of the output pulley 95 and drives the forward driven roller 51 of the rear auxiliary conveyor 59. When the drive motor 95 is energized, therefore, the conveyors are motivated so that their inner runs 49, 56, and 70 all travel in a forward direction at the same speed. In this manner, letters 26 are fed in spaced, single file relation between the inner runs 40 and 56 from the rear inner roller 32 along the sensing path 83 through the juncture 78 and into the separating station 85.

Before considering how the size and spacing between adjacent letters 26 are sensed, a description is given of the manner in which the letters are directed into either the acceptance channel 82 or the rejection channel 81 at the separating station 85. Accordingly, a directing unit, generally indicated by the numeral 110, is provided for this purpose and includes a horizontal air nozzle 112 extending through the slot 58 in the return run 57 in forwardly adjacent spaced relation to the juncture 73. The air nozzle includes a tubular section blending into a flattened section which opens through an outlet slot 112 (FIG. 5) from which air is directed under predetermined pressure across the separating station 85 (FIG. 1) toward the run 40 where it extends along the main forward section 76 of the conveyor assembly 25. A funnel 113, mounted in the table 16, is provided for capturing and discharging the air. The slotted nozzle, as disclosed herein, produces an air blast at the optimum impact force, pressure and spread. That is, it is desirable to obtain a high impact force so as to positively deflect the letters as they enter the separating station, to minimize air pressure so as to conserve air and reduce noise level, and to minimize the angle of air spread so that the air blast or stream readily passes through the narrow slot 39 between the belts 37 into the funnel. The subject nozzle is excellently suited for these purposes.

The air nozzle 112 has an inlet portion 115 in which is connected a solenoid valve 117 which automatically opens and closes with starting and stopping of the motor 92, a manual maintenance valve 118, a manually adjustable pressure regulator 11 9, and an air filter 120. A high pressure air source, not shown, is connected to the maintenance valve. A solenoid valve 122, including a solenoid 123 (FIG. 9), is also connected in the inlet portion of the air nozzle (FIG. 1) and is electrically opened or closed for providing, or for shutting off, the blast of air across the separating station 85. For the purposes of the present invention, the solenoid valve has just two positions, namely, an open position with the solenoid 123 energized and a closed position with the solenoid deenergized.

Vlhen the solenoid 123 is energized and a letter 26 of predetermined flexibility has its leading portion 26a (FIG. 6) in the separating station 85 and its trailing portion 26b grasped at, and forwardly propelled through, the juncture 78, said letter is deflected into the acceptance channel 82 by the blast of air, whereas a letter of insufficient flexibility (FIG. 8), that is of predetermined stiflness, is not deflected and therefore passes into the rejection channel 31 and thence into the chute $8. The slot 39 is made narrow so that highly flexible letters are not blown through the slot 39; as explained, the de- 1 scribed nozzle 112 makes such narrowness possible. When the solenoid valve is in its deenergized condition, a letter (FIG. 7) moving through the separating station continues on into and through the rejection channel even if it is of the required flexibility since there is no blast of air to deflect it.

It is also significant that the present apparatus provides a sensing unit, generally indicated by the numeral (FIG. 1), positioned along the sensing path 83, for sensing the letter size and spacing and for controlling the solenoid valve 122 in accordance with predetermined standards of size and spacing. The sensing unit includes a mounting plate 132 secured to the table 16 and projecting up from the supporting surface 17 on the opposite side of the inner run 4-0 from the inner run 56. The sensing unit also includes an electrical system (FIG. 9) which includes a row of lower phototransistors 134439 (FIG. 10) mounted in the plate 132 in the same plane as the slot 39 with the phototransistors being in longitudinally spaced relation along said sensing path 83 (FIG. 1), and an upper phototransistor (FIG. 10) mounted in the plate 132 a predetermined distance above the supporting surface 17, it being noted that the upper photo- -ransistor is also above the belts 37 and 55. The phototransistors 134-138 in said row and the upper phototransistor 149 are hereinafter referred to as conditioning phototransistors whereas the forwardmost phototransistor 134 in the row is hereinafter referred to as the signaling phototransistor since these terms indicate their main functions in the electrical system of FIG. 9.

The sensing unit 13% (FIG. 1) also includes front and rear, generally parabolic reflectors and 146 mounted on the table 16 on the opposite side of the rear section 75 of the conveyor assembly 25 from the mounting plate 132. Lamp holders 147 are mounted within the reflectors (FIG. 3), and light bulbs 148 are supported in the lamp holders. When the bulbs are lighted, light rays are reflected by the reflectors and beamed through the slots 39 and 58 onto the photo-transistors 134-139 in the described lower row thereof. Further, the front reflector has an upper opening 149, and light passes through this opening, then through a double convex lens 150 and is reflected by a mirror 151 across and over the rear conveyor section '75 onto the upper phototransistor 140. Although not shown, it is preferable to enclose the sensing unit 130 and to blow air into such enclosure through a needle valve 156 connected to the inlet portion 115 of the nozzle 112; in this manner dust is minimized in the sensing unit.

It is believed understood, therefore, that when no letters 26 are being conveyed along the sensing path 83, all of the phototransistors 134-149 are illuminated and energized. When a letter moves along the sensing path, however, it interrupts the beams of light and darkens, that is deenergizes, one or more of the phototransistors. The combinations of phototransistors which are darkened and illuminated, and the timing thereof, indicate the size and spacing of the letters. Energization and deenergization of the phototransisters, therefore, is effective through the electrical system of FIG. 9 to shut off the blast of air from the air nozzle 112 whenever a letter should be rejected, as will be explained in detail below.

Referring specifically to the electrical system of FIG. 9, positive and negative lines 169 and 161 are connected to a source of DC voltage, for example 25 volts. Connected between these lines are a conditioning circuit 162, a signal circuit 163, a coupling circuit 164, a spacing circuit 165, a nullifying circuit 166, a time delay circuit 167, and an output circuit 168. Briefly considering the significant components of these various circuits, the conditioning circuit includes the conditioning phototransistors 134-138 and 1441. The conditioning phototransistors 134, 135, 136 and 137 have their bases connected to the positive line and their collectors connected through diodes 170 to a conditioning transistor 171. The

phototransistor 138 has its base connected to the base of the conditioning transistor and its collector connected to the negative line. The upper conditioning phototransistor 140 has its base connected to the positive line and its collector connected to the collector of the conditioning transistor. The conditioning circuit also has an output terminal 172 at the base of the upper conditioning phototransistor. It will be noted that not all of the circuit components are specifically described and for these, reference is made to FIG. 9.

The signaling circuit 163 includes the signaling transistor 139 which has its base connected to the positive line 160 and its collector connected to the negative line 161. It is to be noted that none of the emitters of the several phototransistors 134-140 are connected in the outside circuits. The collector of the signaling phototransistor is also connected to a signaling transistor 174 having its emitter connected through a zener diode 175 to the positive line and its collector connected to the negative line. The signaling circuit has an output terminal 176 at the collector of the signaling transistor.

The coupling circuit 164 includes a coupling transistor 178 having its collector directly connected to the positive line 160, its emmiter connected to the negative line 161, and its base connected to the output terminal 172 of the conditioning circuit 162. The emitter of the coupling transistor is also connected to a main coupling diode 179. The output terminal 176 of the signaling circuit 163 is connected through a diode 180 to the base of the coupling transistor.

The spacing circuit 165 provides a monostable multivibrator 185 and an amplifying transistor 186 connected through an input capacitor 187 to the output terminal 176. The spacing multivibrator includes an output transistor 188 connected through a pair of diodes 189 to the base of the coupling transistor 178, an input transistor 190 connected from the collector of the output transistor to the base of the amplifying transistor, and a resistancecapacitance combination 191 for determining the time in which the multivibrator is in its semistable condition.

The nullifying circuit 166 is provided to nullify the effect of the spacing circuit 165 and includes a bi-stable multivibrator 192 having left and right transistors 193 and 194, and an inverting transistor 195 connected to the main coupling diode 179 by an input line 197 and having an output connected to the left nullifying transistor. An amplifying transistor 199 has its output connected to the left nullifying transistor through line 200, and an input line 201 connects the base of the amplifying transistor to the output terminal 176 of the signaling circuit 163. Furthermore, the nullifying circuit 166 has an output line 202 interconnecting the nullifying multivibrator 192 and the base of the output transistor 188 in the spacing multivibrator 185.

The time delay circuit 167 includes a monostable multivibrator 205 and a resistance-capacitance combination 207 which determines the time in which the time delaying multivibrator is in its semistable condition. The time delay multivibrator has its input connected to the main coupling diode 179.

The output circuit 168 provides input transistor 209 connected to the output of the time delay multivibrator 205 and a resistance-capacitance combination 211. The output circuit has an output transistor 210 connected to the positive line through a diode 212 and to the negative line 161 through the air valve solenoid 123.

The operation of the present separating apparatus is described at this point. In order to place the apparatus in operating condition, the drive motor 92 is energized whereby the valve 117 opens and the runs 40, 56 and 70 travel forwardly, preferably at a speed of one hundred and ten inches per second, the bulbs 148 are energized to illuminate the phototransistors 134 to 140 inclusive, and DC. voltage is applied across the positive and negative lines 160 and 161 of the electrical system thereby energizing the solenoid 123 and opening the valve 122 whereby a blast of air issues from the nozzle 112. The pressure of the air blast is adjusted by the regulator 119.

When the subject apparatus is used for separating letters 26, the primary purpose of the apparatus is to remove from a continuous how of the mixed singulated letters, that is, letters spaced in a single file procession, all those letters which are outside of a predetermined range of sizes, all those letters which are too stiif, and all those letters which are not spaced far enough away from their respective preceding letter-s. For example, the range of standard sizes may be from 3% inches to 11% inches long and 2% inches to 5% inches wide; stifl? letters may be defined as those which are not deflected seventeen degrees by an air blast of forty p.s.i. issuing from the air nozzle 112, and wherein the nozzle is spaced longitudinally from the juncture 78 by a distance of 3% inches; and the standard minimum space between successive letters may be 2% inches. It is evident, of course, that the invention is not limited to these specific values, nor to other specific examples given throughout the specification, but that these values and examples are given only to aid in understanding the invention.

Thus, assuming that letters 26 are fed in spaced, single file relation between the input rollers 31 and 53 (FIG. 1), the conveyor assembly 25 moves the letters along the sensing path 83. Before the letters reach the separating station 85, the phototransistors 134-140 sense the size and spacing between the letters and shut off the air blast it the letter is too long, too wide, too short, or too close to the preceding letter; letters of standard size and spacing do not turn off the air blast but are subjected to a stiffness test in the separating station. The operation of the electrical system (FIG. 9) under each of these conditions is separately described below. But initially, however, several general statements about the system will aid in understanding how the system operates under these various conditions. With reference to FIGS. 1 and 9, it is first to be noted that the air blast from the nozzle 112 is normally on but is turned off by a reject signal conducted through the main coupling diode 179, the delay circuit 167 and the output circuit 168, the latter deenergizing the solenoid 123 in response to the reject signal. Second, as each letter 26 darkens the signaling pho-totransis-tor 139, a positive reject signal or pulse is developed at the output terminal 176. Third, the nearly positive line voltage at the terminal 172 normally conditions the main coupling diode 179 to conduct such a reject signal. Fourth, this conducting condition of the main coupling diode is not changed by letters of nonstandard sizes so that these letters are rejected. Fifth, a letter of standard size substantially reduces the voltage at the terminal 172 whereby the main coupling diode is reverse-biased so as to block the reject signal.

With these general operational conditions in mind, when a letter 261 which is too long (FIG. .10) moves along the sensing path 83, the row of lower phototransistors 134-139 are all darkened at some instant. Darkening of the phototransistors134-138 causes the voltage at the base of the conditioning transistor 171 (FIG. 9) to remain low so that this transistor remains in its conducting condition. Also, because the signaling phototransistor 139 is darkened, a reject signal passes from the terminal 176 through the main coupling diode 179 to the delay circuit 167 whereupon the delay multivibrator 205 is driven into its semistable condition. After a predetermined time delay, determined by the R-C combination 207 and sufiicient to allow the leading portion 26a of the long letter 261 to emerge from the juncture 78, the delay multivibrator returns to its stable condition whereupon it triggers the output circuit 168 which thereby deenergizes the solenoid 123 and turns off the air blast. Therefore, the letter 261 is conveyed into the rejection channel 81 (FIG. 7), The output circuit re-energizes the solenoid after a predetermined interval, determined by the R-C combination 211, sufiicient to allow the leading portion 26:: of the '3 rejected letter to project between the separating block 89 and the auxiliary forward section 77 of the conveyor assembly 25.

If a letter 26w is too wide (FIG. 11), the upper phototransistor 144i is darkened whereupon the previously described conditioning voltage at the output terminal 172 is unchanged so as to maintain the main coupling diode 179 in a signal conducting condition. Therefore, when the signaling phototransistor 139 is darkened by the leading portion 26a of the wide letter 26W, a reject signal causes such letter to be rejected in the same manner as the letter which was too long, as described above.

When a letter 26s is too short, it fails to darken the phototransistors 13S and 139 simultaneously (FIG. 12). With all of the phototransistor-s 134-138 illuminated, therefore, they are all conducting and place the conditioning transistor 171 in a nonconducting or oil condition. Thus, the conditioning voltage at the terminal 172 remains at substantially the positive line voltage whereby the main coupling diode 179 remains in its signal conducting condition. The reject signal generated by the darkening of the signaling phototransistor 135 by the short letter 26s is thus conducted through the main coupling diode and the short letter is rejected in a manner now believed understood.

With reference to FIGS. 9 and 13, the operation of the electrical system with regard to spacing control (FIG. 13) is as follows. As the trailing portion 25b of each letter 26' passe-s beyond, that is forward of, the signaling phototransistor 139, a negative spacing signal or pulse is developed at the output terminal 176. This spacing signal triggers the spacing multivibrator 185 into its semistable condition whereby the main coupling diode 179 is maintained in its signal conducting condition irrespective of the voltage at the terminal 172. The spacing multivibrator remains in its semistable condition for a predetermined spacing time, determined by the R-C combination 191, just short of the time required for a properly spaced succeeding letter 25" to darken the signaling phototransistor. If such a succeeding letter 25" darkens the spacing phototransistor .within said predetermined spacing time, a reject signal is generated, as before, and is conducted through the main coupling diode to deenergize solenoid 123 and to reject the succeeding letter.

Still considering spacing control, the nullifying circuit 166 is actuated each time a letter 26 is rejected because of length or width, that is the reason for nullifying circuit is to disable the spacing circuit 165 whenever a letter is rejected since the removal of a letter (by rejecting it) from the procession of letters increases the spacing between the two adjacent letters which remain in the procession so that adequate spacing then exists.

The operation of the nullifying circuit 166 is best eX- plained by reference to FIGS. 9 and 13. In FIG. 13, it is to be assumed that the leading letter 26 will be rejected when it reaches the separating station 85, that the trailing letter 26" is of standard size, and further, that the distance between the leading letter 26 and the trailing letter 2s" is less than the predetermined standard, that is, in the present example, less than 2 /4 inches. The cycle of the nullifying multivibrator 1% is initiated by the reject signal conducted through the main coupling diode 1'79 when the leading letter 26 darkens the signaling phototransistor. When the trailing portion 26b of the leading letter 26 moves forward of the signaling phototransistor and causes it to be illuminated, the spacing signal developed thereby at terminal 176, in addition to being applied to the spacing multivibrator 135, is fed through the amplifying transistor 199' to the nullifying multivibrator whereby the cycle of the nullifying multivibrator is completed and a nullifying pulse is applied to the output transistor 133 of the spacing multivibrator. This nullifying pulse cancels the pulse from the amplifying transistor 186 so that the spacing multivibrator remains in its stable condition and the main coupling diode 179 is not affected by the spacing circuit 155. As will be specifically described below, however, the main coupling diode is reverse-biased by the standard size trailing letter so that when this trailing letter darkens the signaling phototransistor, the reject signal developed thereby is blocked. Therefore, the trailing letter 26", even though it may have been too close to the leading letter 26 along the path 83, is not rejected, assuming that it is of standard size and flexibility. It is believed understood that the nullifying multivibrator is reset only when a reject signal is conducted through the main coupling diode.

A standard size letter 26 passing along the sensing path 83 is illustrated in FIG. 14. With such a letter, the signaling phototransistor 139 and at least the forwardmost lower conditioning phototransistor 138 but no more than the four lower conditioning phototransistors -132 are simultaneously darkened. The significant effect of a standard letter on the system is that it causes both the conditioning transistor 171 (FIG. 9) and the upper conditioning phototransistor to conduct so that the voltage at the terminal 172 is substantially reduced whereby the main coupling diode 179 is reverse-biased, that is, is in a nonconducting state. Accordingly, the reject signal caused by the standard size letter darkening the signaling phototransistor 13% is not conducted through the main coupling diode and does not cause deenergization of the solenoid 123.

Assuming that a letter 2d is of standard size and is not too closely spaced to a previous letter, it is submitted to a stifiness test at the separation station 85. That,

is, as the leading portion 26a of such a letter moves into the air blast (FIG. 6), the trailing portion 26b is still grasped between the belts 37 and 55 at the juncture 78. If the letter is flexible enough, the air blast bends the letter about said grasped trailing portion and forces the leading portion into alignment with the acceptance channel where it is conveyed by the main forward section 76 of the conveyor assembly 25 out of the subject apparatus. If the letter is too stiff (FIG. 8), the air blast is not sufficiently strong to align the leading portion of the letter with the acceptance channel so that the letter remains aligned with the rejection channel into which it is conveyed for discharge into the rejection bin 33. It is understood, therefore, that letters which are acceptable as to size and spacing, but are unacceptable as to the stiffness, are rejected without the necessity of a reject signal from the electrical system.

It will be evident from the foregoing that the subject apparatus separates articles, such as letters, on the bases of at least five different rejectable conditions although using only one diverting unit, that is the solenoid valve, controlling an air blast. Since the air blast is normally turned on, no electrical signal is needed for accepting or rejecting articles for stiffness and the control solenoid is actuated only for articles of non-standard size and spacing. Furthermore, by disabling the spacing circuit when a letter is rejected, the minimum desired article spacing is obtained while preventing undesirable rejections of standard articles. The apparatus is adjustable, has a minimum of moving parts, does not jam or damage articles handled, and can process articles at a high volume, for example up to about 800 letters per minute.

Although a preferred embodiment of the present invention has been shown as described, it will be under-v stood that changes and modifications may be made in the details thereof without departing from the spirit and the scope of the appended claims.

The invention having thus been described, what is believed to be new and desired to be protected by Letters Patent is:

1. Apparatus for sorting flat, flexible articles according to their degree of flexibility comprising a conveyor including a portion for gripping opposite flat sides of the articles and conveying the articles along a delivery path;

an air jet nozzle, said nozzle being spaced downstream of the article gripping portion of said conveying means and at one side of the article delivery path; the spacing of said nozzle from said gripping means being substantially less than the length of the articles, so that when a leading portion of each article is opposite said nozzle, the trailing portion of the article remains gripped by the gripping portion of said conveyor; first and second article receiving channels downstream of said air jet nozzle, said first channel having an article receiving portion that is aligned with said delivery path for receiving relatively stifl articles, said second channel having an article receiving portion that diverges from said delivery path for receiving relatively flexible articles; means for maintaining a normally flowing jet of air through said nozzle for simultaneously testing the flexibility of all artices that pass the air jet nozzle and diverting the relatively flexible articles into said second channel, said jet of air permitting the relatively stiif articles to continue on into said first channel.

2. The method of directly sorting flat, flexible articles in accordance with their degree of flexibility, comprising the steps of simultaneously advancing a train of the articles along a path while gripping the flat sides of the articles, successively laterally freeing one side of the leading portion of each leading article in the train while continuing to grip and advance the trailing portion of the article, and successively subjecting the other side of the leading portion of each article to a laterally directed, continuously flowing jet of air while the trailing portion of the article is gripped, for flexing the leading portions of all of said articles having less than a predetermined stiffness out of their path of advancement.

References Cited by the Examiner UNITED STATES PATENTS 1,483,059 2/24 Pool.

2,138,645 11/38 Rey 209-75 3,035,694 5/62 Hirschfeld.

3,065,850 11/ 62 Nixon 209-75 FOREIGN PATENTS 1,215,444 11/59 France.

OTHER REFERENCES German application, 1,062,465, printed July 30, 1959.

ROBERT E. REEVES, Acting Primary Examiner.

5 ABRAHAM BERLIN, Examiner. 

1. APPARATUS FOR SORTING FLAT, FLEXIBLE ARTICLES ACCORDING TO THEIR DEGREE OF FLEXIBILITY COMPRISING A CONVEYOR INCLUDING A PORTION FOR GRIPPING OPPOSITE FLAT SIDES OF THE ARTICLES AND CONVEYING THE ARTICLES ALONG A DELIVERY PATH; AN AIR JET NOZZLE, SAID NOZZLE BEING SPACED DOWNSTREAM OF THE ARTICLE GRIPPING PORTION OF SAID CONVEYING MEANS AND AT ONE SIDE OF THE ARTICLE DELIVERY PATH; THE SPACING OF SAID NOZZLE FROM SAID GRIPPING MEANS BEING SUBSTANTIALLY LESS THAN THE LENGTH OF THE ARTICLES, SO THAT WHEN A LEADING PORTION OF EACH ARTICLE IS OPPOSITE SAID NOZZLE, THE TRAILING PORTION OF THE ARTICLE REMAINS GRIPPED BY THE GRIPPING PORTION OF SAID CONVEYOR; FIRST AND SECOND ARTICLE RECEIVING CHANNELS DOWNSTREAM OF SAID AIR JET NOZZLE, SAID FIRST CHANNEL HAVING AN ARTICLE RECEIVING PORTION THAT IS ALIGNED WITH SAID DELIVERY PATH FOR RECEIVING RELATIVELY STIFF ARTICLES, SAID SECOND CHANNEL HAVING AN ARTICLE RECEIVING PORTION THAT DIVERGES FROM SAID DELIVERY PATH FOR RECEIVING RELATIVELY FLEXIBLE ARTICLES; MEANS FOR MAINTAINING ANORMALLY FLOWING JET OF AIR THROUGH SAID NOZZLE FOR SIMULTANEOUSLY TESTING THE FLEXIBLIT OF ALL ARTICLES THAT PASS THE AIR JET NOZZLE AND DIVERTING THE RELATIVELY FLEXIBLE ARTICLES INTO SAID SECOND CHANNEL, SAID JET OF AIR PERMITTING THE RELATIVELY STIFF ARTICLES TO CONTINUE ON INTO SAID FIRST CHANNEL. 